The invention relates to a device for retrieving foam rubber, spherically shaped cleansing bodies, which are circulated discontinuously through the cooling system of a tubular heat exchanger or the like. The device includes a cylindrical housing divided into two chambers by a sieve, and it has feed, discharge, drain and flushing tubes and valves for opening and closing the tubes.
It is conventional to clean the pipes of a water-cooled, tubular heat exchanger with spherically shaped cleansing bodies. They are made of foam rubber, or a similar material, have a diameter slightly larger than the inner diameter of the pipes, are pumped into the cooling water, and are subsequently forced through the pipes. After the cleansing bodies have passed the heat exchanger, they are retrieved from the cooling water by means of a filtration device and reintroduced into cooling water which flows toward the heat exchanger. Due to friction the cleansing bodies are subject to wear and abrasion. As their diameter decreases they must be removed from circulation and replaced.
German patent publication No. 12 38 939 accomplishes this by incorporating an interceptor apparatus in the system. Such an interceptor has a cylindrical housing divided by a cylindrical filter sieve into an inner, cylindrical chamber, connected to feed and discharge tubes, and an outer annular chamber, connected to drain and flushing tubes. The tubes extend from the chamber in a radial direction and a valve is attached to each tube. The valves can be set to allow the cleansing bodies to flow through the opened feed tube into the inner cylindrical chamber, where they are retained by the filter sieve. The water carrying the cleansing bodies flows through the sieve into the annular chamber and is discharged through the opened drain tube. When the cleansing bodies retained by the sieve are to be recirculated into the cooling system, the discharge and flushing tube valves are opened. This directs flushing water into the annular chamber and forces the cleansing bodies from the inner chamber and into the discharge tube. When all four valves are closed the cylindrical housing can be opened up, and the cleansing bodies trapped in the sieve can be removed, sorted and those with excessively reduced diameters are replaced. This requires four valve which must be controlled and operated to regulate the water flow so that water can pass through, or cleansing bodies can be retrieved and inspected. This requires generally, complex, costly electronic controls and a corresponding number of actuating motors. Additionally, the typically used ball valves wear out quickly and thereby lose their seal.
The arrangement disclosed in German Pat. No. 32 18 386 employs chambers formed in a cylindrical housing by several partitions which are rotatable about the housing axis. The chambers are subdivided into two chamber groups by a filter plate positioned perpendicular to the partitions and the housing axis. One of the two chamber groups retrieves the cleansing bodies. Each chamber group is fitted with feed and discharge tubes attached to the ends of the housing. The chambers are alternatingly rotated to communicate with the tubes leading to and from the tubular heat exchanger. Such a construction is complex and the rotating chambers result in frequent breakdowns. To prevent a short circuiting of the water in the retrieval apparatus several chamber groups are required.
It is also known to mount a box-like housing with associated valves in the feed and discharge tubes of surface condensors or surface heat exchangers. Swiss patent 462 566 discloses to provide a control shaft having two valve plates or disks each of which cooperates with a valve seat on such a box-like housing. By coupling two or more pairs of valve plates it is possible to alternately connect two or more distribution tubes with a feed tube. However, such valve plates are unsuited for retrieving spherically shaped cleansing bodies.